Stairs provide a vertical means of moving through a space and are critically important to circulation for buildings with multiple floors. The design of stairs is so important because you need to get two things up and down them: your self/family/visitors, and… your furniture!

Towers have traditionally been used as communication spaces. They provide an easy place to locate stairs and even elevators for those that need this. Also, if you include operable windows at the top floor of your stair tower and open the windows on the side the wind is heading, the tower will act like a chimney, and will draw the warm air up from the lower floors, where it can be used to warm the space or allowed to exit through vents and create a fresh air flow through the entire house. Stair tower “chimneys” are especially useful tools in hot climates when we want to get that hot air out fast and naturally.

The Building Code generally limits the distance between floors to 12 feet, and the final floor-to-floor height has a direct impact on the design of stairs because we want to make treads and risers all the same height and depth so they are easy to navigate. The best stairs are designed with a maximum of 7 inches of rise for every 11 inches of run. When we can, in our office, we do that one better and make it 7:12. It makes it easier for my big size 9 foot to fit the tread. It also makes the math easier. But, it does mean a longer set of stairs. We use that to our advantage though, and build in drawers, cabinets, closets, bookcases, and other storage into the space below.

The easiest stairs to build are straight-run type, but sometimes these stairs can be a little “long” and a landing at the halfway point is useful. These stairs can also take up a large amount of space. Another option is to use a U-shaped stair, which uses the least amount of space. When landings are used, they should be at least as deep as the stairs are wide. Landings at eye level or below are the easiest to use.

Winders are the angled steps used in some places in lieu of landings. These are difficult for children, parents with armloads full of anything (especially squirmy kiddos), and older people to navigate, so we recommend using a landing instead. Rails should be 2 inches wide, located a minimum of 1 ½ inches away from the wall, should be placed at 2’-6” to 2’-10” above the top joint of the riser/tread, and headroom above the treads should be 6’-8” or greater.

While many people use found stones to build short stair sections in Earthships, we have found that these are troublesome. They often have different riser heights, which messes with people’s equilibrium, and their rugged and uneven surfaces encourage tripping. A “dressed and finished” stone step is cut level. This much safer option can be well worth the expense, if it helps you to avoid having to call an ambulance when someone takes a bad spill.

Dual Staircases

Old homes often had a main and rear staircase, with the rear staircase being smaller in most cases, as it was mostly for emergencies and household staff (and teenagers sneaking in and out). These days, even though most of us do not have household staff anymore, everyone needs to get around equally easily, and Codes want you to have two ways out of the upstairs. Dual staircases might be a good way to go, just make sure that the tread width meets Code.

Spiral stairs use the least amount of space in plan, but they are often not allowed by Code because they are quite dangerous. They are also difficult to manage for long term regular use. If they are allowed, it is usually only as a secondary access to a loft space. Per Code, the spiral stair option only applies if the lofted space is 400 square feet or less.

We always try and avoid putting a single step anywhere in our designs, whether in the landscape, along a corridor, up to a room, or even out into the garage. Our minds just do not process spatial information in singularities - we do much better if there are two steps instead of one. How many times have you launched off a single tread step that you have used a hundred times before? Probably at least a few. Good design practice for small stairs is 2 risers minimum, with a 7:12 ratio of rise to run or riser to tread. In cases where only one stair is needed, you might consider using a ramp, with a 1:12 maximum rise to run and a non-slip surface.

Banisters and balusters

We love the creative railings used in Earthship designs. Just be aware that balusters and banisters on stair rails should be spaced such that a 6” ball cannot pass between any two members in order to meet Code. This keeps your kiddos’ heads from getting caught when they are playing around railings.

For furniture, I offer this chart which I scanned into my computer several years back. I’m not sure anymore where it is from, but it’s a great design tool if you want to get that bed or sofa up to the loft or second floor.